Air Conditioning - Which system for second floor???

Four years ago, I bought a 1926 Colonial Revival in the upstate of South Carolina. My house is approx. 1550 sq. feet, two floors. The main floor is heated with a natural gas furnace - nice, warm heat!! - but the second is heated and cooled by two old vents left over from the coal furnice days. Upstairs is about 700 sq. feet - two bedrooms and a bath. One vent in each bedroom fed from the first floor system. In the summer the second floor gets pretty warm and in the winter, pretty cool. I'm currently doing reseach and getting quotes on a system for the second floor. I get mixed information - one company told me to go with another gas furnace -1.5 tons, SEER 13 - and the other that I've had in thus far said to go with a heat pump 1.5 tons, SEER 13. He said that the main load would be for cooling, not heating. Said that during the winter, heat will rise from the first floor and will help to keep the second floor warm with the heat pump. I grew up with a heat pump - efficient but kind of drafty! As I mentioned, my house was build in 1926 thus NO insulation in the walls but the attic and floor are well insulated. Still have the original one-payne (pain!) windows - looking to get storm windows in 2007 to cut the infiltration. I live in a historic district thus vinyl windows are a "no-go". I LOVE gas but was prices these days, a few cold weeks can take a huge chunk out of my checking account. I want to be comfortable and penny wise.

Any advice is very much appreciated!!

Thanks in advance!

Did anyone do a manual j/ load calc for your 2nd floor? You wont know exactly what you need until someone does this. Just looking around by them might be giving you those different results. Since you are pennywise like me I would keep getting quotes and doing research but start but fixing the cheaper things first. Storm windows will give you a very good ROI as well as a few tubes of caulk on the baseboards and other gaps.
You say your attic is well insulated but is it well air sealed? If you have alot of air drafts getting into the house an equal amount of your heated air is leaving it too. Check all penetrations into the attic to make sure they have caulk or spray foam around them. If you have dormers and or kneewalls make sure theres insulation correctly put there. Your walls could use some insulation too but its more involved (but not a super difficult diy).
How many return vents do you have up there? Its hard to put air in an area with not enough returns so look at your ductwork to see if that can be upgraded.
All those things are important to do and way cheaper than getting a new heat pump or furnace for a small 2nd floor. If you do actually still need a upstairs system after all that it will most likely be a much smaller one and thus cheaper than what you require right now.

Heat pump will is the onlyway to go in SC

Thanks for the advice thus far! Since my initial post, I've had a couple of more estimates and it seems like the heat-pump is perhaps the way to go. I got the first quote back and it was almost 59 hundred bucks! :eek: I'm hoping to get another couple of quotes in a few days but I was taken aback somewhat with the price!

I've been reading other threads regarding makes of systems - where one company has different brand-names, Trane and American Standard, etc. What about Goodman? The reason that I bring it up is that an estimater installs Trane and Goodmans. He mentioned that the Goodman is as good as Trane (if they're rated SEER-13 - they all have to conform to the same specs and that the warrenty is pretty much the same), but that the Goodman costs less. My question is that if they're basically the same thing, why does the Trane cost more? Is it just name recognition? :confused: Ugh!

This really should be a no-brainer but I just don't want to make a $6K mistake! Maybe I'll just get a window a/c unit for the summer and an electric blanket for the winter. :)

Still seeking advice.

Thanks in advance!